Alpha-phenyl-upsilon-(2-pyridyl)-butyric acids



United States Patent 2,713,051 a-PENYL-y-(Z-PYRIDYD-BUTYRIC ACIDS Lewis A. Waiter, Madison, Richard H. Barry, Bloomfield, a -d John R. Clark, Nutley, N. L, assignors' to Wallace & .ticrnan incorporated, a corporation of Delaware No Drawing. Application June 16, 1953, Serial No. 362,152

8 Claims. (Cl. 260-295) OCHrCHrC-COOH in which formula R represents hydrogen, lower alkyl radicals having from 1 to 6 carbon atoms, lower alkenyl radicals, benzyl, and phenyl.

The compounds of the present application are valuable choleretic compounds. They are also useful as chemical intermediates for the production of other compounds which are valuable antispasmodics, such conversion being eii'ected by converting the carboxyl group to an amide or an ester group, followed by reduction of the pyridine group to a piperidine group.

The present application may be considered to be a continuation-in-part of applicants copending application, Ser. No. 134,858, filed December 23, 1949, and now abandoned for a-Phenyl-y-(Z-Pyridyl)Butyronitriles while disclosing the identical chemical formulae of the compounds herein claimed and the identical processes for preparing such compounds. Some additional matter is presented in the present application as to the uses of the compounds of the present application.

There is also copending herewith another application of the present inventors, Ser. No. 376,992, which is related to application Ser. No. 134,858 aforesaid in the same way as the present application. The line of division between application Ser. No. 376,992 and the present application is based on the fact that in applicants copending application Ser. No. 376,992 aforesaid, the compounds claimed are all nitriles, and contain the group CN; while the present application claims the butyric acids, containing the group COOH.

The compounds of the present application may be prepared by a process, which provides a means of introducing an amino group into phenyl acetom'triles without the use oi the toxic amino alkyl halides (nitrogen mustard gases) commonly used.

W e have discovered that 2-vir1ylpyridine may be reacted under proper conditions with phenylacetonitriles in the presence of certain strongly basic catalysts to give a-phenyl- -(2-pyridyl)-butyronitriles in good yields.

The butyronitriles above may then be converted to the corresponding butytic acids by hydrolysis of the nitrile two 200 ml. portions of water.

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group in the presence of an acid, such as sulfuric acid as follows:

The following examples serve to illustrate our invention.

EXAMPLE I a-PhenyZ-y- (Z-pyridyl) butyronitrile Four grams of sodium was dissolved in 400 ml. of absolute isopropanol and 200 g. of benzyl cyanide (phenyl acetonitrile) was added to the cold solution. It was well stirred and a solution of 190 g. of freshly distilled 2-vinylpyridine in 800 g. of benzyl cyanide was added. The flask was warmed gently and an exothermic reaction took place which caused the temperature to rise to about 55 to 60 C. After one hour at this temperature the mixture was heated on a steam bath for several hours.

One liter each of water and ether was added and the mixture was made just acid to litmus with acetic acid. The ether layer was separated, washed with water, and the basic materials were removed by extracting with two 500 ml. portions of 10% hydrochloric acid followed by The combined acid extracts were shaken with ether, to remove a little non-basic material and after separation they were made strongly basic with sodium hydroxide. The oil which separated was taken up in ether, Washed with water and was then heated in a high vacuum at C. to remove volatile impurities. The product so obtained weighed 350 to 375 g. and was a clear viscous oil which, except for the presence of a small amount of polymeric 2-vinylpyridine, was quite pure. The composition of the material was proved by the fact that it hydrolyzed readily with 50% sulfuric acid to give an excellent yield of a-phenyl- -(2-pyridyl)- butyric acid having the formula:

This compound was soluble in dilute acids and bases but was insoluble in water. It was crystallized from alcohol to give white crystals, M. P. 158 to 160 C. uncorrected. Neutralization equivalent (alkali): calculated-241; found-240.

EXAMPLE II (a) One hundred grams of freshly distilled 2-vinyl pyridine and 200 g. of OC-PhBI'lYl-bLltYi'OIlllI'llC were refluxed for eight hours with a solution of 3 g. of sodium in 500 ml. of absolute isopropanol. The mixture was diluted with 500 ml. of water and extracted with benzene. The benzene extracts were washed with water and the basic materials were then removed by extracting with three ml. portions of 10% hydrochloric acid. The acid extracts were made strongly alkaline with sodium hydroxide solution and the oil which separated. was taken base was obtained by the addition of alkali.

' dilute acids and bases but insoluble in water.

'vacuo on a steam bath to recover 30 g. of Z-Vinylpyridine.

The residue was dissolved in 300 ml. dry benzene and treatedvwith dry hydrogen chloride which precipitated 'to 'g. of polymeric vinylpyridine hydrochloride. This impurity was filtered off. The hydrochloride of the ocphenyl-a-ethyl-y-(2-pyridyl)-butyronitrile was soluble in dry benzene. It was extracted with water and the free The 100 g. of product so obtained was a clear viscous oil, which was quite pure ex'ce'ptfor the presence of a little polymeric 2- vinylpyridine. This product was hydrolyzed to a-phenyla-ethy1- -(2-pyridyl)-butyric acid in good yield by heating it with 70% sulfuric acid at 150 C. for twelve to eighteen hours. This compound has the formula @CHMDHQO OH (kHz-CH3 The white crystalline acid so obtained was soluble in It crystallized from alcohol and melted at 200 C. to 202 C. uncorrected. Neutralization equivalent (alkali): found-- 267; calculated-269.

(b) One gram of sodium amide was added to a solution of 25 g. of oz-phenylbutyronitrile in ml. of dry toluene. This mixture was stirred until the sodium amide dissolved and a solution of 20 g. of 2-vinylpyridine in 25 g. of a-phenylbutyronitrile was added. The mixture was slowly warmed to 100 C. and after several hours at that temperature, was worked up in the same manner as described in part. (a) above to give a-phenyl-a-ethyl- -(2- pyridyl) -butyronitrile.

EXAMPLE III a-Pl zenyl-a-n-butyl-y-(Z-pyridyl) -butyronitrile This compound was prepared from 117 g. of u-phenylcapronitrile, g. of 2-vinylpyridine and 400 ml. absolute isopropanol containing 4 g. of sodium using the same procedure used in Example II(a); The g. of clear viscous product so obtained gave no crystalline salts, but .was hydrolyzed to buty'ric acid in good yield as described in Example II. The acid so obtained melted at 201 C. to 203.5 C. uncorrected and was soluble in dilute acids and bases. Neutralization equivalent (alkali) calculated297; foun'd-- 296. This acid has the formula N CHTCHTC'CO OH HrCHz-CHz-CHa EXAMPLE IV V a-Phenyl-a-methyl-y-(Z-pyridyl) butyronitrile This compound was prepared from g. c t-phenylpropionitrile, 80 g. 2-vinyl-pyridine and 400 ml. absolute isopropanol containing 4 g. of sodium, using the same procedures as in Example II(a). The g. of. clear viscous product so obtained gave no crystalline salts, but was hydrolyzed to a-phenyl-a-methyl-y-(Z-pyridyl)- butyric acid in good yield as described in Example II(a). The acid so obtained melted at 149 C. to 152 C. uncorrected, was soluble in dilute acids and bases, and had a neutralization equivalent as actually determined of 254,

V as compared with the theoretical value, calculated-255.

a-phenyl-a-n-butyl-y-( 2-pyridyl) This acid has the formula CH -C -C-C O OH N/ 2 Ha I OH: EXAMPLE v a-Phenyl-u-benzyl-y- (Z-pyridyl) -butyr0nitrile Sixty-nine grams of benzyl-phenylacetonitrile, 33.5 g. 2-vinylpyridine and 300 m1. absolute isopropanol in which 3 g. of sodium had been dissolved were refluxed for eight hours, then diluted with 300 ml. of water. The crystalline product which separated on cooling was filtered off and crystallized from methanol and found to have a melting point of 118 C. to 120 C. uncorrected.

This product was hydrolyzed with 70% sulfuric acid to a-phenyl-a-benzyl-y-(Z-pyridyl)-butyric acid, melting point 228 to 229 C. uncorrected. Neutralization equivalent: calculated-331; found-332. This acid has the formula EXAMPLE v1 a,a-Diphenyl-'y-(2-pyridyl)-butyr0nitrile Two hundred grams of diphenyl acetonitrile, 100 g.

' of 2-vinylpyridine and 1500 ml. absolute isopropanol in which 10 g. of sodium had been dissolved were refluxed for eight hours, then diluted with 1500 ml. of water. The crystals which precipitated on cooling were filtered oif and crystallized from methanol to give g. of the desired product, having a melting point of 120 C. to 122 C. a

This product was hydrolyzed with 70% sulfuric acid to a,a-diphenyl-'y-(2-pyridyl)-butyric acid, having a melting point with decomposition of 258 C. to 265 C. uncorrected. Neutralization equivalent: calculated- 317; found-315. This acid has the formula EXAMPLE VII m-Phenyl-a-allyl-y-(Z-pyridyl)-butyronitrile V Eighty grams of a-phenyl-u-allyl-acetonitrile, 50 g. of 2-vinylpyr1'dine and 400 ml. of isopropanol in which 4 g. of sodium had been dissolved were refluxed for eight hours and the mixture was worked'up as described in Example II(a). The product was a clear, slightly yellow oil, which was proven to be ahenyl-u-alIyI-v-(Z- pyridyl)-butyronitrile, by reactions described in Example V III below.

EXAMPLE VIII a-Phenyl-a-h-propyl-ry-(Z-pyridyl)butyronitrile Nineteen grams of the u-phenyl-a-allyl-v-(2-pyridyl)- butyronitrile (produced as set forth in Example VII) was hydrogenated in alcohol with a palladium charcoal catalyst at room temperature. The theoretical amount of hydrogen necessary to saturate the double bond was absorbed in a few minutes and no further reduction took place. The catalyst was filtered off and the solvent was distilled to leave the u-phenyl-a-n-propyl-y-(Z-pyridyl)- butyronitrile as a li ht yellow oil. it was hydrolyzed With 70% sulfuric acid to give u-phenyln-n-propyly- (2-pyridyl)-butyric acid, having a melting point of 205 C. to 207 C. uncorrected. Neutralization equivalent: calculated283; found284. The acid thus produced has the formula out-onion on AIHrCHz-CHG EXAMPLE IX u-Phenyl-afi-mezhylallyl (2-pyria'yi -buryr0nitri l e Ninety-eight grams of a-phenyl-u-(p -methylallyl)- acetonitn'le (prepared from sodio-benzyl cyanide and methyl allyl chloride by the conventional alkylation procedure), 60 g. of 2-vinylpyridine and 500 ml. of isopropanol in which 5 g. of sodium had been dissolved were refluxed for eight hours, then worked up as described in Example 11((1). The 104 g. of clear, slightly yellow, oily product so obtained was characterized by hydrolysis with 70% sulfuric acid. The crude product was taken up in ether and extracted with dilute alkali. Acidification of the alkaline extract gave a-phenyl-a-(fimethylallyl)-- -(2-pyridyl)-butyric acid, having a melting point of 173 .-l76 C. Neutralization equivalent: calculated295; found-303. The formula of this acid is @CHz-CHz-C-COOH When this acid was dissolved in excess 5% alkali and boiled with charcoal for fifteen minutes, subsequent acidification of the filtered solution gave an acid having a melting point of 194 C. to 197 C., and a neutralization equivalent of 296, which may have been the result of a shift of the double bond.

There has been described hereinabove certain new compounds. The range of equivalents has been pointed out in respect thereto. A procedure for the making of various example compounds within the original general disclosure is also included. It is recognized that certain equivalents will occur to those skilled in the art from the foregoing particular description. All such equivalents as reasonably come within the scope of the appended claims are intended to be included in the purview thereof.

What is claimed is:

1. A compound of the class consisting of the butyric acids having the formula i on-on-o-ooon 5. A compound having the formula @omomo-ooon (IJHZOHZ 6. A compound having the formula @GHTCHTC'COOH 7. A compound having the formula OHz-CHa-C-COOH N l 8. A compound having the formula I OHz-OHz-C-COOH Hi-C=CHz References Cited in the file of this patent UNITED STATES PATENTS Hartmann et a1 May 16, 1950 FOREIGN PATENTS Great Britain June 25, 1947 OTHER REFERENCES Panizzon: Chem. Abst., vol. 40, p. 3117 (1946). 

1. A COMPOUND OF THE CLASS CONSISTING OF THE BUTYRIC ACIDS HAVING THE FORMULA 